Introduction
“Dissolved solids” refer to any minerals, salts, metals, cations or anions dissolved in water. Total dissolved solids (TDS) comprise inorganic salts (principally calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfates) and some small amounts of organic matter that are dissolved in water. The total dissolved solids is determined by filtering a measured volume of sample through a standard glass fiber filter and it is the portion of the total solids that passes through the filter.The concentration of the dissolved ions may cause the water to be corrosive, salty or brackish taste, result in scale formation, and interfere and decrease efficiency of hot water heaters.
Objective(s) of the Experiment
This test is carried out in order to determine the amount of dissolved solids in water.
Equipments and Materials Needed
- Filter Paper
- Evaporating dish
- Measuring Cylinder
- Weighing balance
- Oven
- Desiccator
Procedures
- Prepare evaporating dish by heating it to 180°C and store in desiccator until needed.
- Weigh the dish prior to use. Weight of dish = B
- Wash the filter paper
- Stir the sample
- Pipette 50ml into the filter while stirring
- Filter and wash three times
- Transfer filtrate into the evaporating dish and evaporate to dryness in the drying oven (make sure the temperature is below boiling point as to prevent splattering)
- Dry evaporated sample for at least one hour at 180°C±2°C.
- Cool in the desiccators to balance temperature
- Weigh. Weight of dried residue + dish = A
- Repeat cycle of drying, cooling and weighing until the weight change is less than four per cent.
- Analyse at least 10 per cent of all samples in duplicate. Duplicate determinations should agree within five per cent of their average weight.
Results and Calculations
- Total Dissolved Solids TDS (mg/L)
Where:
- A = Weight of dried residue + dish (in mg).
- B = Weight of dish (in mg).
References
- Hydrology Project Training Module File. ‘How to Measure Dissolved, Suspended and Total Solids’
- The University of Western Australia; School of Civil, Environmental and Mining Engineering. ‘Determination of Solids’. http://www.ceme.uwa.edu.au/research/laboratories/water-quality/protocols/solids. Assessed March 9, 2018.
- Water Research Center. ‘Total Dissolved Solids and Water Quality’. https://www.water-research.net/index.php/water-treatment/tools/total-dissolved-solids. Assessed June 20, 2018.
Download “Total Dissolved Solids in Water”
Total-Dissolved-Solids-in-Water.docx – Downloaded 0 times – 23.79 KB
